1. Field of the Invention
This invention relates to information storage systems and, in particular, to adapter mechanisms to allow information to be recovered from a storage medium by a recording or playback device designed for use with either a different type of storage medium or a plurality of types of storage media.
2. Discussion of the Related Art
Because of the multiplicity of options for data storage media, data often needs to be transferred from one recording or playback device designed for use with one type of storage medium to another device designed for use with a different type of storage medium. In order to avoid data duplication, adapters have been developed to allow use of different types of storage media within a single device.
One example of such an adapter is the phonograph adapter, which allows a single phonograph player to recover information from phono-graph records designed to be played at 331/3 revolutions per minute, and from phonograph records designed to be played at 45 revolutions per minute, as well as other rotational speeds.
Another example is a permanent hub adapter used in testing laboratories for adapting a Compact Disc--Read Only Memory (CD-ROM) disc for use with a magneto-optical (MO) spindle. This type of hub adapter consists of two magnetizable rings and several screws. The CD-ROM disc is placed between the magnetizable rings, and the rings are screwed together through the CD-ROM disc. This hub adapter essentially drills holes through the CD-ROM disc. Therefore, the adapter is permanently mounted to the disc, and the disc thereafter can not be played in a CD-ROM player.
A further example is a hub adapter designed for commercial or consumer use. The hub adapter consists of a plastic housing, a magnetizable ring, and a connector. The magnetizable ring is mounted within the plastic housing such that the ring may spin relative to the housing. The connector consists of a plurality of plastic tabs extending is from the housing in the direction away from the ring. Each plastic tab has a foot at the end remote from the ring. The hub adapter is designed such that two adapters will fit together with the CD-ROM disc in between. The feet of one adapter snap into a recess in the other adapter, creating a permanent connection. Again, the adapter is not removable, and the CD-ROM disc can no longer be played in a CD-ROM player. Furthermore, this design allows slippage of the CD-ROM disc relative to the adapter during rotation.
There are several options for storage media for computer or other data. Among these options are Compact Disc--Read Only Memory (CD-ROM) discs and magneto-optical (MO) discs. Each of these choices presents certain advantages and disadvantages compared to the other.
Because of these relative advantages and disadvantages, it is often advantageous to store some data on storage media such as CD-ROM discs and other data on storage media such as MO discs. However, this storage option previously had required multiple playback devices. When the amount of data reaches levels where a jukebox is needed for data storage, this storage option requires multiple jukeboxes, dramatically increasing cost and space requirements.
The International Organization for Standardization (ISO) sets industry standards for certain aspects of information-bearing media and playback or recording devices for those media, including CD-ROM discs and MO discs. The standards cover such aspects as media shape and size, hub diameter, and clearance between drive mechanisms and media.